Class Notes Honors Biology

“LIFE CHEMISTRY”

Water•The most important property of the water molecule is that it is charged on each end

MOLECULE

WATER

O

H

H +

-

Mixture:•Substance composed of two or more elements or compounds that are mixed together but not chemically combined

•ex - salt and pepper / sugar and sand

Suspensions:•Mixture of water and a non-dissolved material

•Material does not dissolve and does not settle in the liquid

•It remains ‘suspended’•Ex - Blood, Oil and Water, Gravy

Solution:A substance dissolves in another

Ex - Sugar in water

Solvent:•The substance that does the dissolving

•Ex - The water

Solute:•The substance that is dissolved

•Ex - The sugar

Acids and

Bases

Acids:•Compounds that release hydrogen ions ( H + ) into solution

•Ex - Hydrochloric acid (HCl)•HCl ---> H+ + Cl -

Acids tend to have the following characteristics:•ionize in water to generate hydrogen ions [H+]

•turn litmus paper RED •induce a sour taste (e.g. lemon)

•have a pH less than 7

Bases:•Compounds that release hydroxide ions (OH - ) into solution

•Ex - Sodium Hydroxide (NaOH)•NaOH ---> Na + + OH -

Bases tend to have the following characteristics: •ionize in water to generate hydroxide ions [OH-]

•turn litmus paper BLUE •induce a bitter taste •feel slimy•Have a pH more than 7

 Look at each of the following

product and see if you can guess if it is an

ACID or a BASE....

ACID OR

BASE?????

ACID

ACID OR

BASE?????

BASE

ACID OR

BASE?????

ACID

ACID OR BASE ?????

ACID

ACID OR

BASE?????

BASE

ACID OR BASE ?????

ACID

pH Scale:•A measurement system that indicates the relative concentrations of hydrogen ions [H+] and hydroxide ions [OH-]

•pH Scale runs from 0 to 14•A difference of 1 on the scale is

actually a difference of 10 times the relative strength of the acids or bases:

• ‘0’ means 100 = 1• ‘1’ means 101 = 10• ’2’ means 102 = 100• ‘3’ means 103 = 1000 etc.....

pH scalePage 66 in your book

Incr

easi

ngly

Aci

dic

Incr

easi

ngly

B

asi

c

Neutral

0

14

12

3

4

5

9

8

7

6

13

12

11

10

Stomach Acid

Lemon Juice

Vinegar/Cola

Lye

Tomatoes

Household Bleach

Household Ammonia

Normal rainwater Shampoo

Soap

Urine

Baking Soda

Human BloodSea Water

Tears

SalivaWater

Oven Cleaner

•Acidic = 0 to 6 = H+ ion

concentration (0 is highly acidic)

• Neutral = 7 = Equal conc. of H+ and OH-

ions (water)•Basic = 8 to 14 = OH- ion

concentration (14 is highly basic)

• Neutralize an acid by adding a base• Neutralize a base by adding an acid

• H+ + OH- -----> H2O

Inorganic vs Organic Compounds

•Organic means the compound contains Carbon

•Inorganic means it does not contain Carbon

Carbon:•Living things contain carbon•Carbon is special because of the strong and stable bonds that it can form

•Carbon has 4 electrons in its second energy level

•This means that it can form 4 single covalent bonds

Polymerization:•Large compounds (polymers) formed from smaller ones (monomers)

•Macromolecules: are giant polymers

4 Basic Molecules of Life:

• CARBOHYDRATES• LIPIDS• PROTEINS• NUCLEIC ACIDS

CARBOHYDRATES : (Sugars and Starches) Contain energy stored in the bonds that make the molecules

When the bonds are broken the energy is released

Glucose is the basic energy source for organisms

3 Kinds of Carbohydrates: MONOSACCHARIDES

DISACCHARIDES

POLYSACCHARIDES

MONOSACCHARIDES : MONO means “ONE” 3 KINDS:GLUCOSE (sugar in green plants)

FRUCTOSE (sugar in fruit)

GALACTOSE (sugar in milk)

Formula is C6H12O6 They differ

in the arrangement of atoms

DISACCHARIDES : DI- means “TWO” 3 KINDS: SUCROSE - Table Sugar

(glucose + fructose)

LACTOSE - Milk Sugar (glucose + galactose)

MALTOSE - Malt Sugar (glucose + glucose)

POLYSACCHARIDES : -POLY- means “MANY”

Made of long strings of simple sugar molecules

POLYSACCHARIDES : 3 KINDS

- STARCH-

CELLULOSE - GLYCOGEN

STARCH A Large Storage Molecule in Plants

Found in potatoes, bread, pasta, etc.

CELLULOSE A large molecule used as Structure in Plants (Fiber)

Fiber is Important in Human Diet

Cannot be digested in Humans - Cleans your Intestines

GLYCOGEN Large storage molecule in animals

Broken down for energy as you need it

Dehydration Synthesis:Dehydration = loss of water Synthesis = putting together

This reaction forms complex carbohydrates by combining two or more monosaccharides

Each time a bond is formed, a molecule of water is removed (dehydration)

Hydrolysis : Reaction occurs when polysaccharides are split apart to form monosaccharides

Means “water splitting” Reverse reaction of dehydration synthesis

LIPIDS :•Organic compounds that are waxy or

oily•Made of Fatty Acids + Glycerol

•Used to store energy, form biological membranes, used as chemical messengers

•FATS / OILS / WAXES / PHOSPHOLIPIDS / STEROLS

FATS / OILS / WAXES :•Fats and waxes are solid at room

temperature, oils are liquid•Plants and animals use lipids to

store energy•When broken down, lipids produce

more energy than carbohydrates •Fats can be Saturated or

Unsaturated or Polyunsaturated

•Saturated - Has every carbon joined by a single bond, it contains the maximum number of hydrogen atoms

•Unsaturated - contains a pair of carbons that is joined by a double bond

•Polyunsaturated - contains several double bonds

•Polyunsaturated fats are liquid at room temperature and are used as cooking oils. Ex - sesame oil, peanut oil, corn oil, olive oil

•Replacing saturated fats in your diet with polyunsaturated fats may help prevent heart disease

PHOSPHOLIPIDS :•Contains parts that dissolve well

in water and parts that don’t dissolve well in water

•Liposomes - spontaneous forming balloon-like structures with a double layer of lipid molecules (“lipid bilayer”)

•Lipid Bilayers form Cell Membranes

STEROL LIPIDS :•Important in building cells and

carrying messages from one part of the body to another (hormones)

•Cholesterol - common sterol - important in many animal cells - if excessive in diet, it is a risk factor in heart disease

PROTEINS : FUNCTIONS of Proteins include:

Movement, Structure, Transport, Biochemical Control, Storage, Regulation, Defense

Are Polymers of more than 20 different AMINO ACIDS

Peptide Bond: Type of covalent bond that joins two amino acids

Catalyst: Any substance that speeds up the

rate of chemical reactions without being changed by the reaction

They work by lowering the “start-up” energy of a reaction

Enzymes are the catalysts in living organisms

Enzymes: are a special group of proteins that speed up the chemical reactions that are necessary for the ordinary activities of life

simple cell may contain over 2000 different enzymes, each a catalyst for a different reaction

Substrates: are the substances that are affected by an enzyme

Active Site: the region that substrates bind to on an enzyme (like a “Lock and Key”)

Regulating chemical pathways, synthesizing materials needed by cells, releasing energy, and transferring information

Involved in digestion, respiration, reproduction, vision, movement, thought, and even making other enzymes

Enzyme Functions:

NUCLEIC ACIDS : Polymers of Nucleotides

2 Kinds :RNA Ribonucleic Acid - Makes Proteins

DNA Deoxyribonucleic Acid - Store and Transmit Genetic Information

pH scale

Page 66 in your book

Incr

easi

ngly

Aci

dic

Incr

easi

ngly

B

asi

c

Neutral

0

14

12

3

4

5

9

8

7

6

13

12

11

10

Stomach Acid

Lemon Juice

Vinegar/Cola

Lye

Tomatoes

Household Bleach

Household Ammonia

Stomach Acid

Normal rainwater Shampoo

Soap

Urine

Baking Soda

Human BloodSea Water

Tears

SalivaWater

Oven Cleaner

Copy this

scale for your notes